1. Field of the Invention
The present invention relates to a radio selective calling receiver and, more particularly, to a radio selective calling receiver which can eliminate display noise during a display operation.
2. Description of the Prior Art
A radio selective calling receiver is generally called through the use of a call number assigned thereto. General radio selective calling receivers are designed to display information such as a message on the display section. For example, some receivers are designed to always display the time, and others are designed to reduce the current consumption by keeping the display power supply off normally.
Recently, there have been increasing number of radio selective calling receivers which have been equipped with a variety of functions which can be set by the switching operation performed by users, e.g., the memo function, the telephone directory function, and the function of exchanging stereotyped expressions created by the users, instead of just being used for calling operations by the users. Under the circumstances, a relatively large number of radio selective calling receivers are designed to perform various display operations.
The display means of many such receivers display information on liquid crystal displays (LCDs). Such a display means boosts a voltage in an LCD driving section, and displays information on the LCD at the boosted voltage. When the voltage is boosted, noise tends to occur. The radiation of this LCD driving noise may adversely affect the radio section.
For this reason, LCD driving noise may noise cause a deterioration in the sensitivity of many radio selective calling receivers. Some radio selective calling receivers are therefore provided with measures to reduce the noise.
For example, the radio selective calling receiver disclosed in Japanese Unexamined Patent Publication No. 3-162136 is provided with the following measure to reduce such noise at the display section. The frame that supports the display section is made of a conductive member and directly connected to the ground line (the ground of the substrate) of the receiver. With this structure, the impedance of the ground line of the receiver is decreased to improve the shielding effect.
According to this conventional radio selective calling receiver, since the frame that supports the display section is made of a conductive member, the cost is high as compared with a case in which the frame is made of a resin material. In addition, the frame may cause electric contact with other parts, and a deterioration in sensitivity and the like occur because of the influences of noise radiations to the antenna.